Closed Bug 1763724 Opened 8 months ago Closed 29 days ago

Firefox excessive battery drain on MacBook (apple silicone)


(Core :: Performance, enhancement)

Firefox 99





(Reporter: craig.stowers, Unassigned, NeedInfo)


User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.4 Safari/605.1.15

Steps to reproduce:

I ran a bunch of popular websites, scrolled up and down and tracked CPU and energy impact in Activity monitory for a variety of Mac browsers.

I tested Twitter, Amazon, Facebook, Udemy, Gmail and many other websites the results were always consistent.

This Reddit post shows others share the issue:

Actual results:

Firefox draws at least twice as much power for the same tasks as other browsers (according to Activity Monitor). While Chrome/Brave/Edge maybe max out at 10-20 on the energy impact panel... Firefox can sometimes hit 60. Not only that but Firefox can idle at worryingly high levels.

Even waving the mouse around Firefox window uses far more energy than waving it around Brave or Safari.

If I have a day of browsing, with Firefox my battery lasts maybe 6 hours, but if I use Chrome or Brave it lasts 10 hours. Keep in mind this involves a lot of idle time - if the browser was constantly in use the relative difference would be greater.

Is it possible it's a frame rate thing relating to the new 120hz screens? I do notice Firefox seems smoother than competition.

Expected results:

I'd expect the difference between browsers to not be this huge. It's a real shame for people like me who work undocked half the week and prefer Firefox. It's a deal breaker for me and many others.

The performance was no better after I removed all extensions, cleared caches, and reset all settings to default.

OS: Unspecified → macOS
Hardware: Unspecified → ARM64

The Bugbug bot thinks this bug should belong to the 'Core::Networking' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Component: Untriaged → Networking
Product: Firefox → Core
Component: Networking → Performance

Could you create a performance profile using and share the profile here (there is upload button in the profiler)

Flags: needinfo?(craig.stowers)

With no answer from the reporter, we don’t have enough data to reproduce and/or fix this issue. Please reopen or file a new bug with more information if you see it again.

Closed: 29 days ago
Resolution: --- → WORKSFORME
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